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Redstone Dust Test

This is a test case of redstone dusts: is a "fence gate/detector rail BUD", manually controlled by the lever and a wire that the BUD will detect what changes in the wire will update the fence gate.
Changes in the red blocks update the face gate, in the blue don't. The iron blocks near the fence gate will logically update the fence gate.
The conclusion is that changes in redstone dust, even if the levels don't change, causes updates, even to air.
This unfinished study is based on this topic: http://www.reddit.com/r/redstone/comments/12txhi/i_get_why_this_happens_but_it_still_seems_like/